Re: ntpd stratum 1 funny offset with NetBSD 6 branch

Hi Simon !
Two observations:
NetBSD 5 has 4.2.4p6.
NetBSD 6+current have 4.2.6p5.
Also note that the PPS samples seems to be ~two seconds apart and there is
also a difference of ~2 seconds between now and the asser time stamp.
The ATOM driver should be just using the difference between the fictive
integral second and the time stamp. So from the data given ATOM's behavior

looks strange here. Even more so as the other peers seem to indicate
basically

good synchronization.
Further step:
Verify that PPS is picked up correctly:
- go to /src/external/bsd/ntp/dist/util and make pps-api
- call pps-api with your PPS device
If all is well (NetBSD 6.99.20) you should see something like this:
1374221788.000029243 1374221788.200063352 267915 267916 0.200034109
1374221789.000023787 1374221788.200063352 267916 267916 -0.799960435
1374221789.000023787 1374221789.200024162 267916 267917 0.200000375
1374221790.000023219 1374221789.200024162 267917 267917 -0.799999057
This is a GPS receiver with a 200ms PPS pulse. The 23usec offset comes from
the RS232 external status interrupt path.

Another driver of mine reads high resolution time stamps (100ns) via
PCIe and feeds that

oscillators).
So you must be seeing PPS information ~1 second apart. For some time
I have the suspicion the the CD interrupt is not always correctly picked up,
but I have not been able to prove that as the issues went away on ntpd
restart.
Frank
On 07/19/13 06:30, Simon Burge wrote: